As the most common human malignancy, skin cancer is a major public health concern. Ultraviolet radiation (UVR), specifically that produced by indoor tanning booths contributes significant risk for skin cancer. Indoor tanning is becoming increasingly prevalent and is particularly popular among adolescent and young adult females. While many indoor tanners tan for appearance reasons, a subgroup of frequent tanners may become psychologically and physically dependent on tanning. There is evidence that UVR exposure produces substances in the body (e.g., the opioid beta-endorphin) that may increase positive feelings and the desire to tan. The primary aim of the proposed project is to test the feasibility and acceptability of a novel experimental paradigm to investigate the affective (emotional) and biological determinants of and responses to UVR exposure that may motivate ongoing indoor tanning behavior. 18-25 year-old female frequent and infrequent indoor tanners will be recruited and randomly assigned to receive UVR and non-UVR (placebo) light from standard commercial tanning booths in a within-subjects cross-over design. Participants will complete a psychological interview, questionnaires, and blood samples before and after UVR exposure. It is hypothesized that there will be significant differences between the frequent and the infrequent indoor tanners in psychological/affective and biomarker (ACTH, beta-endorphin) baseline levels and responses to UVR exposure, as well as genetic polymorphisms (the mu-opioid receptor, OPMR1). Our team has successfully conducted several previous skin cancer prevention and addiction studies with young adults;thus, we are ideally suited and uniquely poised to conduct the proposed project. Such innovative and translational work is important to understanding the psychological and biological processes underlying the desire to tan, particularly among frequent indoor tanners who are exposed to the greatest levels of damaging UVR. Better understanding of these processes may facilitate the development of more effective prevention efforts and help guide public policy in this area. PUBLIC HEALTH RELEVANCE: Ultraviolet radiation exposure, especially when from artificial sources such as indoor tanning booths, contributes greatly to skin cancer, the most common form of human malignancy. The proposed study seeks to better understand the psychological and biological processes related to indoor tanning behavior among those at high risk for skin damage: young adult females. Better understanding of these processes may facilitate the development of more effective prevention efforts and help guide public policy in this area.